Definition: The phrase "set upon" means to attack or to start to fight someone suddenly and violently. It can also mean to approach someone with force or aggression.
In more advanced contexts, "set upon" can also imply being overwhelmed or besieged by multiple forces or challenges. For example: - "The manager felt set upon by numerous complaints from employees and clients."
While "set upon" primarily means to attack, it can also imply being pressured or burdened by tasks or responsibilities. For example: - "She felt set upon by her many obligations at work."
"Set upon" is a useful phrase to describe situations of aggression or being overwhelmed.